What are these extra lines called when I move from the cardinal point?

When I move the edge from the cardinal points I see extra lines get added to the side and top.
What are these lines called? Why are the extra lines only visible when I move the edge?

I’m not sure what there name is, but I think there purpose is to tell you where geometry would get added if any of the faces were to stop be co-planar. They seem mostly harmless.

The reason I ask is at one point tonight when I was playing around I seem to have done something that ended up showing them additional lines, but they stayed showing.

So I have been trying to figure out what they are called to see if there was some additional viewing option that let me make them visible all the time, if that makes any sense.

SU is edges and faces, a face needs 3 edges, if two faces are coplanar, SU hides the triangles, but they are always there…

some, you can make them into hard edges with an eraser tool option [shift + alt on mac]…


They represent “Softened” Edges. Such edges are a form of “Hidden Geometry”.

So, to always see them, check the menu item: View > Hidden Geometry

You can unsoften single ones, by right-clicking and choose “Unsoften”.

To unsoften them all, switch to Wireframe style. Window select the whole object, and uncheck the “Soft” property in the EntityInfo inspector.

TIP: To have better control over what gets selected (without needing to change rendering style [to hide faces,]) install ThomThom’s Selection Toys extension.

Under the hood, all faces are triangulated. One of the special things about SU, is its ability to have co-planar faces appear and act as a single planar face.

I understand that what SketchUp uses are polyfaces, so that a face can have more than three vertices. The under-the-hood triangulation is only what OpenGL does to display them.